Several people have reported in the past that a couple of Twiddler3 buttons stick.
My first Twiddler3 had sticky buttons, while the second Twiddler3 worked perfectly.
Today I found a possible reason as of to why this might happen.
Yesterday I took apart my Twiddler3 to solder a wire (it's a separate story).
After I put Twiddler back together, I noticed that several buttons stick. Especially the top left button "SP". And no buttons were sticking before.
So I took Twiddler apart again to examine and noticed that I accidentally reversed the two clusters of buttons (as I have no labels on the buttons). I noticed that one of the cluster of buttons has "ABEF" marking on it, and it was in the wrong place.
When I put clusters where they belong, the stickiness of the buttons disappeared.
I realize reversing button clusters is not something an average user of the Twiddler would do.
I'm sharing my experience so that the manufacturer can tell us what their thoughts about this issue.